Rapid communication: effects of Steris 1 sterilization and Cidex ortho-phthalaldehyde high-level disinfection on durability of new-generation flexible ureteroscopes

BACKGROUND AND PURPOSE

The effects of commonly used reprocessing methods on flexible ureteroscope longevity have never been examined. We prospectively studied the effects of Steris 1 sterilization and Cidex ortho-phthalaldehyde (OPA) high-level disinfection (HLD) on the image quality, physical structure, and deflective properties of two new flexible ureteroscopes.

MATERIALS AND METHODS

Two identical "out-of-the-box" Storz 11278AU1 flexible ureteroscopes (Karl Storz Endoscopy, Tuttlingen, Germany) were sterilized individually using the Steris 1 system (Steris Mentor, Ohio) or disinfected with Cidex OPA (Advanced Sterilization Products, J&J, Irvine, CA) for 100 trials followed by a crossover to the other method for another 100 trials over a period of 1 year. After every five trials, optical quality, angle of deflection, and fiber damage were analyzed in the laboratory. Throughout the study, neither of these ureteroscopes was used clinically.

RESULTS

After 100 trials, ureteroscope 1, which was sterilized initially in the Steris system, had a 12-mm tear on its shaft (noted after the 17th trial), 297 damaged fibers, and a 37% drop in resolution (loss of 3.75 lines/mm). There was no change in deflection from baseline. In contrast, after 100 cycles, ureteroscope 2, which was subjected to HLD with Cidex OPA, had no visible external damage, a 0% change in resolution, 10 damaged fibers, and no change in deflection. After the crossover, ureteroscope 2 developed a semilunar defect that obscured the endoscopic view, whereas there was no further significant damage to ureteroscope 1.

CONCLUSION

After 100 cycles, the Steris 1 system rendered the flexible ureteroscope unusable, whereas HLD with Cidex OPA had minimal adverse impact.

Prevention of disease transmission during flexible laryngoscopy

The medical literature was reviewed to evaluate the risk of disease transmission and nosocomial infection associated with flexible laryngoscopes. These instruments have been reported to be contaminated with blood, body fluids, organic debris, and potentially pathogenic microorganisms during routine clinical use. Failure to reprocess properly a flexible laryngoscope may, therefore, result in patient-to-patient disease transmission. Different types of biocidal agents, including 70% isopropyl alcohol, quaternary ammonium compounds, and 2% glutaraldehyde have been reported to be used to disinfect flexible laryngoscopes. A logic, or algorithm, was developed to evaluate the adequacy of these and other types of biocidal agents used during instrument reprocessing. This review determined that flexible laryngoscopes are semicritical instruments that require high-level disinfection (or sterilization) to prevent nosocomial infection. Whereas 70% isopropyl alcohol, quaternary ammonium compounds, and other products that achieve intermediate-level or low-level disinfection are contraindicated for reprocessing flexible laryngoscopes, 2% glutaraldehyde and other products that achieve high-level disinfection (or sterilization) are recommended for reprocessing these instruments to prevent nosocomial infection. A formal set of step-by-step guidelines for reprocessing flexible laryngoscopes is provided. Use of a disposable sheath to cover and protect the flexible laryngoscope from contamination during clinical use is discussed.

Dear Los Angeles Times: the risk of disease transmission during gastrointestinal endoscopy

This is the second in a series of articles that review media reports investigating the risk of disease transmission associated with gastrointestinal flexible endoscopy. The first article in this series, "

COMMENTARY

Do Scopes Spread Sickness?'' was published in this journal in 1999 (Gastroenterology Nursing, 22(4), 179-180).

Epidemiology and Prevention of Infections Related to Endoscopy

Contaminated endoscopes are the most common cause of device-related nosocomial outbreaks in the United States. Because almost all outbreaks are related to breaches in reprocessing techniques, it is crucial that endoscope cleaning and disinfection are performed carefully. Key elements that should be emphasized are availability of and adherence to guidelines, thorough staff training, and ensuring proper equipment is used in the reprocessing. Encouraging endoscopists to notify infection control when they see unexpected postprocedure complications and document which endoscopes are used in each case are key elements in limiting the impact of outbreaks.

Symptoms and lung function in health care personnel exposed to glutaraldehyde

BACKGROUND

Glutaraldehyde is widely used as a disinfectant for endoscopic equipment. The aim of this study was to investigate work practices and glutaraldehyde exposure in relation to symptoms and lung function.

METHODS

A questionnaire was administered to 76 nurses. Exposed nurses (n = 38) also completed lung function tests and visual analogue scales before and after a work session in which glutaraldehyde exposure occurred. Disinfection activities were timed and counted, personal exposures established, and control measures documented.

RESULTS

Exposure values above the exposure limit (0.10 ppm) were found for all exposure control methods except for the enclosed washing machine. Skin symptoms were 3.6 times more likely to be reported by exposed workers. None of the other symptoms were significantly associated with glutaraldehyde exposure. There were significant cross-shift reductions in FVC and FEV(1) in the exposed group. No evidence of a dose-response relationship for symptoms or lung function was found.

CONCLUSIONS

Further exposure controls for both glutaraldehyde and gloves are required to improve skin care in glutaraldehyde exposed nurses. Exposure monitoring methods also need review.

Current instrument reprocessing practices. Results of a national survey

In June 1998, a questionnaire was mailed to approximately 2,900 healthcare professionals to assess current instrument reprocessing and infection control practices and determine whether they have changed during the past decade. Surveys were returned from 146 respondents whose facilities performed gastrointestinal endoscopy. Most respondents were registered nurses and almost all worked in healthcare facilities located in the United States. More than 75% of the respondents reported that infection control practices in endoscopy have improved during the past 10 years. Most respondents used glutaraldehyde to reprocess flexible endoscopes. Immersing endoscopes for 20 minutes at room temperature was commonly practiced. Almost 75% of respondents used an automated device to reprocess flexible endoscopes. Most respondents terminally rinsed the endoscope's channels with 70% alcohol followed by forced-air drying. Few respondents outsourced instruments to a commercial reprocessing company and almost 50% reused disposable items. While some practices in endoscope reprocessing have changed during the past several years, others have not. In general, infection controls appear to have improved during the past decade, with the possible exception of a trend to reuse single-use items.

Nosocomial transmission of imipenem-resistant Pseudomonas aeruginosa following bronchoscopy associated with improper connection to the Steris System 1 processor

OBJECTIVE

To assess nosocomial transmission of imipenem-resistant Pseudomonas aeruginosa (IRPA) following bronchoscopy during August through October 1998.

DESIGN

Traditional and molecular epidemiological investigation of a case series.

SETTING

University-affiliated community hospital.

PATIENTS

18 patients with IRPA bronchial-wash isolates.

INTERVENTIONS

We reviewed clinical data, performed environmental cultures and molecular analysis of all IRPA isolates, and observed disinfection of bronchoscopes.

RESULTS

Of 18 patients who had IRPA isolated from bronchoscopic or postbronchoscopic specimens, 13 underwent bronchoscopy for possible malignancy or undiagnosed pulmonary infiltrates. Following bronchoscopy, 3 patients continued to have IRPA isolated from sputum and demonstrated clinical evidence of infection requiring specific antimicrobial therapy. The remaining 15 patients had no further IRPA isolated and remained clinically well 3 months following bronchoscopy. Pulsed-field gel electrophoresis revealed that all strains except one were >95% related. STERIS SYSTEM 1 had been implemented in July 1998 as an automatic endoscope reprocessor (AER) for all endoscopes and bronchoscopes. Inspection of bronchoscope sterilization cycles revealed incorrect connectors joining the bronchoscope suction channel to the STERIS SYSTEM 1 processor, obstructing peracetic acid flow through the bronchoscope lumen. No malfunction warning was received, and spore strips remained negative.

CONCLUSIONS

The similarity of diverse connectors and limited training by the manufacturer regarding AER for bronchoscopes were the two factors responsible for the outbreak. Appropriate connections were implemented, and there was no further bronchoscope contamination. We suggest active surveillance of all bronchoscopy specimen cultures, standardization of connectors of various scopes and automated processors, and systematic education of staff by manufacturers with periodic on-site observation.

Pitfalls in endoscope reprocessing: brushing of air and water channels is mandatory for high-level disinfection

BACKGROUND

Endoscopic transmission of pathogens has been reported. Guidelines have been formulated concerning the risk of infection via contaminated suction and accessory channels. Contamination of the other 2 channels for air and water has not been demonstrated. These channels were examined to clarify whether they require cleaning.

METHODS

Endoscopes used for examinations were divided into 2 groups. Group A endoscopes (n = 20) were brushed along the air and water channels. Group B endoscopes (n = 22) were not. After machine reprocessing, specimens were obtained for bacterial culture. The residual protein was measured in the 2 channels by using amido black 10B dye, and results were compared between the 2 groups.

RESULTS

With regard to the air channel, there were no contaminated endoscopes detected in either group. For the water channel, 1 endoscope in group B was positive whereas there were none positive in group A. With regard to quantification of residual protein, brushing diminished the level in both the air and the water channels.

CONCLUSION

The air and water channels can become contaminated. Brushing every channel is mandatory for high-level disinfection. A redesign of the fundamental structure of endoscopes is proposed.

Decontamination of minimally invasive surgical endoscopes and accessories

(1) Infections following invasive endoscopy are rare and are usually of endogenous origin. Nevertheless, infections do occur due to inadequate cleaning and disinfection and the use of contaminated rinse water and processing equipment. (2) Rigid and flexible operative endoscopes and accessories should be thoroughly cleaned and preferably sterilized using properly validated processes. (3) Heat tolerant operative endoscopes and accessories should be sterilized using a vacuum assisted steam sterilizer. Use autoclavable instrument trays or containers to protect equipment during transit and processing. Small bench top sterilizers without vacuum assisted air removal are unsuitable for packaged and lumened devices. (4) Heat sensitive rigid and flexible endoscopes and accessories should preferably be sterilized using ethylene oxide, low temperature steam and formaldehyde (rigid only) or gas plasma (if appropriate). (5) If there are insufficient instruments or time to sterilize invasive endoscopes, or if no suitable method is available locally, they may be disinfected by immersion in 2% glutaraldehyde or a suitable alternative. An immersion time of at least 10 min should be adopted for glutaraldehyde. This is sufficient to inactivate most vegetative bacteria and viruses including HIV and hepatitis B virus (HBV). Longer contact times of 20 min or more may be necessary if a mycobacterial infection is known or suspected. At least 3 h immersion in glutaraldehyde is required to kill spores. (6) Glutaraldehyde is irritant and sensitizing to the skin, eyes and respiratory tract. Measures must be taken to ensure glutaraldehyde is used in a safe manner, i.e., total containment and/or extraction of harmful vapour and the provision of suitable personal protective equipment, i.e., gloves, apron and eye protection if splashing could occur. Health surveillance of staff is recommended and should include a pre-employment enquiry regarding asthma, skin and mucosal sensitivity problems and lung function testing by spirometry. (7) Possible alternative disinfectants to glutaraldehyde include peracetic acid (0.2-0.35%), chlorine dioxide (700-1100 ppm) and superoxidized water. These are very effective, killing vegetative bacteria, including mycobacteria, and viruses in 5 min and bacterial spores in 10 min. An endorsement of compatibility with endoscopes, accessories and processing equipment is required from both the solution/device manufacturer and the endoscope manufacturer. Other important considerations are stability, cost and safety from the user and environmental standpoints. (8) Cleaning and disinfection or sterilization should be undertaken by trained staff in a dedicated area, e.g., SSD or TSSU. A suitable training programme is described. (9) If endoscopes are processed by immersion in disinfectants, harmful residues must be removed by thorough rinsing. Sterile or bacteria free water is essential for rinsing all invasive endoscopes and accessories to prevent recontamination. (10) If an automated washer disinfector is used it must be effective, non-damaging, reliable, easy to use and its performance regularly monitored. (11) If used, washer disinfectors and other processing equipment should be disinfected on a regular basis, i.e., between patients or at the start of each session. This will prevent biofilm formation and recontamination of instruments during rinsing. Disinfection should include the water treatment system, if present. (12) To comply with the Medical Devices Directive, manufacturers are obliged to provide full details on how to decontaminate the reusable devices they supply. This should include details of compatibility with heat, pressure, moisture, processing chemicals and ultrasonics. (13) The Infection Control Team should always be involved in the formulation and implementation of decontamination policies. Wherever possible, the national good practice guidelines produced by the Medical Devices Agency and/or professional societies shoul

Disinfection of endoscopes: review of new chemical sterilants used for high-level disinfection

Chemical sterilants are used to high-level disinfect heat-sensitive semicritical items such as endoscopes. Most endoscopes have been reprocessed between each patient use with glutaraldehyde (>2%) or the Steris System 1. Several new chemical sterilants have been developed recently, including 7.5% hydrogen peroxide, 0.08% peracetic acid plus 1.0% hydrogen peroxide, and 0.55% orthophthalaldehyde. In order to aid the infection control professional in choosing the appropriate disinfection methodology, this article reviews the characteristics, advantages, and disadvantages of high-level disinfectants intended for reprocessing endoscopes.

Are all sterilization processes alike?

Automated processes designed to sterilize reusable medical instruments use heat and low-temperature chemicals. Several factors, including the physical properties of the sterilizing agents and whether all of the instruments' surfaces can be adequately cleaned, can cause significant variations in the reliability and effectiveness of the sterilization processes. Instruments exposed to heat-based sterilization processes pose the lowest probability of transmitting diseases between patients. Heat can conduct through many different types of materials and can destroy microorganisms embedded under layers of patient debris. Studies have demonstrated, however, that--unlike heat--low-temperature chemicals require direct contact with the microorganisms to be effective. Moreover, the complex designs of some instruments can adversely affect the low-temperature sterilization processes' outcomes by hindering cleaning and preventing the flow of low-temperature chemicals to all of the instruments' contaminated surfaces. This article will explore the differences between heat-based and low-temperature chemical processes to help health care providers minimize the risk of cross-infection.

Instrument design and cross-infection

This article reviews recently reported patient-to-patient transmission of disease during endoscopic procedures and discusses several important instrument reprocessing issues. In addition, the author offers several infection control recommendations to minimize the risk of patient infection during endoscopic procedures.

Identification and resolution of contamination causes found in flexible endoscopes

Although not a requirement for quality control in acute care hospitals, one method of maintaining objective data to verify that endoscopes are contaminant free and not a causative factor in nosocomial infectious is the collection of cultures. There are methods of obtaining cultures from the air, water, and suction channels of flexible endoscopes that require adapters and specific procedures. When automatic disinfectors are connected to public water supplies, this factor should be considered when determining a source of contamination.